The present invention relates to a method and device for filtering a biologically derived sample and mixing the sample with a reagent for analysis of an analyte in the sample. Once the sample has been filtered and mixed with the reagent, it can be analyzed using conventional analytical techniques. The sample typically comprises an analyte in the form of a bindable target substance in a biologically derived liquid sample suspected of containing the substance. Many different forms of analytical devices can be used for analysis of the filtered, reagent-mixed analyte. For example, such devices are described in U.S. Pat. No. 5,885,526, incorporated herein by reference. Many of such devices employ reaction membranes onto which a receptor is immobilized capable of specifically binding to the target substances. Typically, the sample to be tested is added dropwise to the reaction membrane. If the target substance is present in the sample, it will bind to the immobilized receptor. Various methods are used to determine whether the target substance is bound to the receptor, thus indicating its presence in the sample. In one commonly used method, an immunologically reactive binding capable of specifically binding the target substance attached to a detectable label is applied to the membrane. In the device of the foregoing patent, the sample is added to the top of and flows through a reaction membrane to an absorbent material beneath the membrane that draws the sample through the membrane.
In the testing of blood sample solutions, a known device is sold by EY Laboratories, Inc under the name WBT(trademark) includes a fluid container with a generally cylindrical reservoir body with one open end mating with a removable closure form a fluid passageway. The closure is in the form of a conical nose portion. A filter is placed in the nose portion across the fluid passageway. Blood is placed into the reservoir body which is sealed to the closure. Fluid reagent can be added to the reservoir. The reservoir body is flexible so that by compression of it the blood is forced through the filter and out a conical outlet in droplets. A filtering device of the foregoing type is then used to supply the filtered blood sample to an analytical device such as the membrane device set forth above. The reagents used to form the analysis, such as labels retained on a reaction surface, are added to the membrane in a separate step after the sample flows through the membrane. This separate step adds time to the assay and reduces the potential for technician error.
According to the invention, a device is provided for filtering a biologically derived sample and for mixing the sample with a reagent. The device comprises a fluid container defining a reservoir compartment and including a container outlet, a filter and a fluid flow-through matrix disposed in a flow path between the reservoir compartment and the container outlet. Water-soluble, dried reagent is retained on the matrix. Means is provided for urging sample in an aqueous liquid in the reservoir compartment through the filter and matrix and out the container outlet.
In another aspect of the invention, a method is provided for filtering a biologically derived sample including at least one analyte and mixing the sample with a reagent for analysis of the analyte. The method includes applying pressure to the sample in an aqueous liquid in a reservoir compartment of a container to cause the sample to flow in the liquid through a filter and a matrix in the container. The matrix carries a dried, water-soluble reagent which is dissolved producing a filtered aqueous liquid mixture of the reagent and sample. The filtered mixture flows out of the container, so that one or more analytes in the filtered mixture may be analyzed.